Attenuation of ischemia/reperfusion injury in rats by a caspase inhibitor.
BACKGROUND
Z-Val-Ala-Asp(OMe)-CH2F (ZVAD-fmk), a tripeptide inhibitor of the caspase interleukin-1beta-converting enzyme family of cysteine proteases, may reduce myocardial reperfusion injury in vivo by attenuating cardiomyocyte apoptosis within the ischemic area at risk.


RESULTS
Sprague-Dawley rats were subjected to a 30-minute coronary occlusion followed by a 24-hour reperfusion. An inert vehicle (dimethylsulfoxide; group 1, n=8) or ZVAD-fmk, at a total dose of 3.3 mg/kg (group 2, n=8), was administered intravenously every 6 hours starting at 30 minutes before coronary occlusion until 24 hours of reperfusion. At this 24-hour point, hemodynamics were assessed by means of cardiac catheterization; then, the rats were killed, and the left ventricle was excised and sliced. The myocardial infarct size/ischemic area at risk and the count of presumed apoptotic cardiomyocytes (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling [TUNEL]-positive cells) within the ischemic area at risk were assessed through triphenyltetrazolium chloride staining and TUNEL methods, respectively. Peak positive left ventricular dP/dt was higher (P=.02) and left ventricular end-diastolic pressure was lower (P=.04) in group 2 than in group 1. The infarct size/ischemic area at risk of group 2 (52.4+/-4.0%) was smaller (P=.02) than that of group 1 (66.6+/-3.7%), and TUNEL-positive cells were fewer (P=.0002) (group 2, 3.1+/-0.9%; group 1, 11.1+/-1.0%). Agarose gel electrophoresis revealed DNA laddering in the border zone myocardium of group 1, but DNA ladder formation was attenuated in group 2.


CONCLUSIONS
ZVAD-fmk was effective in reducing myocardial reperfusion injury, which could at least be partially attributed to the attenuation of cardiomyocyte apoptosis.
Yaoita
H
H
First Department of Internal Medicine, Fukushima Medical College, Hikarigaoka, Japan. yaoita@cc.fmu.ac.jp
Ogawa
K
K
Maehara
K
K
Maruyama
Y
Y
D000590:Amino Acid Chloromethyl Ketones / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D004587:Electrophoresis, Agar Gel; D005821:Genetic Techniques; D006321:Heart / Q000187:drug effects; D006439:Hemodynamics; D007958:Leukocyte Count / Q000187:drug effects; D008297:Male; D009203:Myocardial Infarction / Q000503:physiopathology; D017202:Myocardial Ischemia / Q000188:drug therapy* / Q000209:etiology; D015428:Myocardial Reperfusion Injury / Q000150:complications; D009206:Myocardium / Q000166:cytology / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley
D000590:Amino Acid Chloromethyl Ketones; D015853:Cysteine Proteinase Inhibitors; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D003546:Cysteine Endopeptidases